Surface control bearing plate

ABSTRACT

A surface plate for supporting generally planar loads, specifically mine roofs. The present invention generally relates to a surface plate that is capable of supporting a mine roof. Surface plates in accord with the preferred embodiments of the present invention comprise a plurality of embossments. The embossments provide the surface plates with increased strength when compared against the prior art. In the preferred embodiments, one of the plurality of embossments is a continuous perimeter embossment that generally parallels the outer perimeter of the surface plate. Another of the plurality of embossments is a circular embossment located at the center of the surface plate wherein a central opening through which a mine roof bolt is received is located. The preferred embodiments may further comprise a plurality of radial embossments that extend from the central embossment to the perimeter embossment. These radial embossments may be arranged in a regular pattern around the central embossment. In one preferred embodiment that is generally rectangular in shape, four radial embossments intersect and extend from the central embossment towards the perimeter embossment and intersect with the perimeter embossment in proximity to the corners of the surface plate.

CLAIM OF PRIORITY

[0001] This application claims the benefit under 35 U.S.C. 119(e) ofU.S. Provisional Application No. 60/278,549 filed Mar. 23, 2001.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention generally relates to load support orbearing equipment and more particularly to load-bearing surface platesadapted to provide support for a generally planar surface. Thisinvention is particularly applicable to mine roof surface plates.

[0004] 2. Description of the Background

[0005] Each year there are numerous reported injuries and multiplefatalities from ground falls in underground coal mines. The vastmajority of these injuries and deaths result from relatively minor fallsof rock from the roof and ribs in coal mines.

[0006] The activity that is most at risk from these minor falls is roofbolting. A large fraction of injuries from roof collapses occurredduring the roof bolting cycle. More importantly, over 75% of both thereported wall and roof fall accidents occurred at or near the workingface of the mine shaft.

[0007] In underground mining operations, it is necessary to support theroof of the mine shaft so that it will not cave in. To provide thenecessary support, large mine bolts are typically set into the roof ofthe mine by mechanical means, resin, or a combination of the two. Themine bolt will often support a bearing plate that is capable ofsupporting the planar surface of the mine roof that is very proximal tothe mine bolt.

[0008] A mine roof bolt is an anchoring device that is typically setinto the roof of a mine to aid in supporting the roof of the mine. Abearing plate is a primarily planar plate that is used to supportportions of a mine roof that are proximal to the mine roof bolt.Generally, mine roof bolts extend through an opening in the center of abearing plate and are secured against the bearing plate to providesupport for the mine roof or walls or other generally planar surface. Asurface plate is a large, primarily planar plate that is used to supportlarge portions of a mine roof in conjunction with a mine roof bolt and abearing plate. An embossment is a three-dimensional surface orprotrusion surface that is raised away from the plane of the bearingplate or surface plate.

[0009] Surface plates are generally much larger than bearing plates andmay be used, generally in conjunction with a bearing plate, to stabilizea larger area of a mine roof that a normal bearing plate would. Aprimary function of surface plates is preferably to maintain and controlthe surface around the roof bolt and bearing plate. Essentially, thesurface plate is designed to maintain a much larger area around the minebolt than a bearing plate. Surface plates are preferably used inconjunction with the standard bearing plates such that these twocomponents work in concert to maintain the roof of a mine. Onedifficulty with fabricating larger surface plates is the additionalweight of such a structure. A need exists to construct large surfaceplates with adequate stiffness and support characteristics that are nottoo heavy to employ easily. Surface plates, with adequate stiffnesscharacteristics, can help minimize or even eliminate progressive roofand rib failures.

[0010] These and other limitations to current implementations of surfaceplates are preferably addressed through the use of the presentinvention. These and other objectives and advantages of the presentinvention will become readily apparent to persons skilled in the artfrom the following description of the preferred embodiments.

SUMMARY OF THE INVENTION

[0011] In accordance with the present invention, there is provided anapparatus for the support of planar surfaces, such as the roof or wallsof a mine shaft. Surface plates in accord with the present inventionhave improved strength and stiffness characteristics compared with theprior art due to at least one but generally a plurality of embossmentsprotruding from the surface of the plate. Generally, the plurality ofembossments comprise a perimeter embossment around the perimeter of thesurface plate, a central embossment centered about a central opening,and a plurality of embossments extending between the central embossmentand the perimeter embossment.

[0012] Surface plates in accord with the present invention allow for thestabilization and support of mine ceilings. The geometry and orientationof embossments on the surface plates in accord with the presentlypreferred embodiments generally provide such surface plates with higherdeflective strength and stability when challenged with a planar loadthan prior art surface plates. Such improvements provide greaterstability and safety for the mining industry.

[0013] In the presently-preferred embodiments of the present invention,a surface plate may be placed on the bolt in conjunction with a bearingplate so the surface plate contacts, bears against, or rests parallel tothe mine roof. The surface plate of the present invention may beconstructed of any substance commonly known in the art. One suchpresently preferred substance is sink steel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The following figures provide further detail of certain of thepresently preferred embodiments of the present invention:

[0015]FIG. 1 displays a preferred embodiment of the present inventiondepicting a surface plate comprising a generally square or rectangularshape and four radial embossments;

[0016]FIG. 2A displays a cross-sectional view of the surface plate ofFIG. 1 along Section 2A;

[0017]FIG. 2B displays a cross-sectional view of the surface plate ofFIG. 1 along Section 2B;

[0018]FIG. 2C displays a cross-sectional view of the surface plate ofFIG. 1 along Section 2C;

[0019]FIG. 3A displays a preferred embodiment of the present inventiondepicting a surface plate comprising a circular shape with a perimeterembossment and four radial embossments;

[0020]FIG. 3B displays a preferred embodiment of the present inventiondepicting a surface plate comprising a generally square or generallyrectangular shape with a perimeter embossment and eight radialembossments;

[0021]FIG. 3C displays a preferred embodiment of the present inventiondepicting a surface plate comprising a generally square or generallyrectangular shape and six radial embossments;

[0022]FIG. 3D displays a preferred embodiment of the present inventiondepicting a surface plate comprising a circular shape and eight radialembossments; and

[0023]FIG. 4 depicts the test setup utilized in the stiffnessexperimental testing of certain preferred embodiments.

[0024]FIG. 5 displays a preferred embodiment of the present inventiondepicting a surface plate comprising a generally square or rectangularshape, four radial embossments and rounded corners.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] It is to be understood that the figures and descriptions of thepresent invention have been simplified to illustrate elements that arerelevant to the preferred embodiments of the present invention, whileeliminating, for purposes of clarity, other elements that may be wellknown. Those of ordinary skill in the art will recognize that otherelements are desirable and/or required in order to implement the presentinvention. However, because such elements are well known in the art, andbecause they do not facilitate a better understanding of the presentinvention, a discussion of such elements is not provided herein. Thedetailed description will be provided hereinbelow with reference to theattached drawings.

[0026] A plurality of surface plate geometries are contemplated withinthe scope of the present invention. While data primarily for generallysquare plates will be discussed, one of skill in the art will recognizethat additional embodiments of the present invention would be generallyrectangular, circular, or of any other geometry that was appropriate forthe specific circumstance confronting the practitioner, as shown by wayof example in FIGS. 1, 2A, 2B, 2C, and 2D. In addition, while thecorners of the surface plate of the depicted presently-preferredembodiments of the present invention are portrayed as clipped along adiagonal line, it is also contemplated that the corners of the surfaceplate may be pointed so that the sides of the plates intersect at rightangles as in a square or rectangular shape.

[0027] In a presently-preferred embodiment of the present invention, thesurface plates may vary in size preferably from about 14 inches by 14inches for a square plate to about 24 inches by 24 inches. One skilledin the art would appreciate that these dimensions could be increased ordecreased to address particular interpretations. Anotherpresently-preferred embodiment of the surface plate comprises a squareplate having the overall dimensions of 15½ inches by 15½ inches. Otherpresently-preferred embodiments may have circular shapes with similardimensions.

[0028] Preferred embodiments of the present invention provide for theinclusion of embossments in the structure of a surface plate. Theembossments enhance the ability of a surface plate to support a planarload. Certain preferred embodiments of the present invention possess aplurality of embossments of varied width and length in the structure ofa surface plate, including an embossment around the perimeter of thesurface plate.

[0029] Generally, preferred embodiments of the present invention allowfor a central opening in a surface plate through which a roof bolt maybe secured into the mine roof. By way of example, one presentlypreferred embodiment, illustrated by a generally square surface plate100, is displayed in FIG. 1. In this preferred embodiment, the surfaceplate 100 has a first surface 104 that is generally planar, except for aplurality of embossments 108, 112, 116 extending therefrom. The surfaceplate 100 also has a second surface, comprising the opposite side of thesurface plate. Note that the second surface, although generally planar,will have the inverse of the plurality of embossments from surface 104which form recessed arrays as the second surface. This plurality ofembossments 108, 112, 116 are preferably incorporated into the structureof the first surface 104 of the surface plate 100, and are disposedaround a central opening 120. As shown in FIGS. 2A, 2B, and 2C, suchembossments 108, 112, 116 comprise portions of the surface plate thathave been molded, stamped, pressed, or otherwise formed such that theyextend a certain height 117, 119, 121 from the first surface of thesurface plate and have a certain width 108, 113. The geometry of theembossments may be varied within the scope of the present invention,such that the face of a particular embossment may be rounded, flat,pointed, or otherwise shaped. A circular embossment 116 is preferablycentrally situated about a central opening 120 in the plate that allowsfor the inserting of a bolt through the plate. The central embossment116 is preferably raised approximately {fraction (5/16)} of an inch inheight from the first surface 104 of the surface plate 100. The face ofthe central embossment 116 is generally flat or planar such that theface of the central embossment 116 is parallel to the first surface 104of the surface plate 100. The central embossment 116 allows the presentinvention to be placed between or over a bearing plate and the mine roofor other planar load. One of ordinary skill in the art will recognizethat the face of the central embossment 116 may be of a differentgeometry than float and may have embossments for on its surface. In onepresently-preferred embodiment, the diameter of the central embossmentis ten times that of the central opening, such that a 6 inch by 6 inchbearing plate only bears against the central embossment and an 8 inch by8 inch bearing plate bears almost entirely against the centralembossment. As shown in FIGS. 2A, 2B, and 2C, the embossments 112, 116preferably protrude away from the planar load that is being supported bythe present invention.

[0030] In one presently-preferred embodiment, the diameter of thecentral embossment 116 is 10 inches although this diameter may bechanged to account for the size of the bearing plate. The bearing plateemployed with the present invention may be oriented such that all sidesof the bearing plate are parallel to the surface plate. Alternatively,it is further contemplated that the bearing plate may be offsetrotationally by any number of degrees.

[0031] In a presently-preferred embodiment as depicted in FIG. 1, anadditional embossment 112 is also located proximal to the perimeter ofthe entire second surface of the bearing plate. As such, as shown inFIGS. 1, 3A, 3B, 3C, and 3D, in certain preferred embodiments, theperimeter of the perimeter embossment 112 is preferably the same shapeas the perimeter of the surface plate 100, e.g. square if the surfaceplate 100 is square, as in FIG. 1. However, the geometry need not matchthe geometry, e.g. the perimeter embossment 112 may be circular whilethe surface plate 100 is square. The perimeter embossment 112 is, incertain preferred embodiments, as depicted in FIG. 1, set back from theedges of the first surface 104 of the surface plate 100 by approximately½ inch. For certain preferred embodiments, such as depicted in FIGS. 1,2A, 2B, and 2C, the perimeter embossment 112 is preferably raised ½ inchin height 119 from the face of the surface plate 100. The width of theperimeter embossment 112 as depicted in FIG. 1, is preferably 1 inch.One of ordinary skill in the art can appreciate that additional widths,heights, and sizes of the perimeter embossment are possible anddesirable depending on the size and loading on the surface plate 100.Notably, the perimeter embossment 112 is preferably proximal to the edgeof the surface plate.

[0032] A presently-preferred embodiment, as depicted in FIG. 1, furtherprovides for embossments 108 extending radially from the centralembossment 116 to the perimeter embossment 112, such that the radial108, central 116, and perimeter 112 embossments may be viewed as forminga continuous embossment. A plurality of radial embossments 108 mayemanate from the central embossment 116. In a presently-preferredembodiment shown in FIG. 1, the radial embossments 112 emanate from thecentral embossment 116 at regular angular spacing and extend outward tothe perimeter embossment 112 perpendicular to the outer perimeter of thecentral embossment 116 at the location that the radial embossment 108intersects the central embossment 116. One skilled in the art willappreciate, however, that the radial embossments 108 may emanate fromthe central embossment 116 in a variety of orientations as shown, forexample, in FIG. 3.

[0033] In one preferred embodiment as depicted in FIGS. 1, 2A, 2B, and2C, the radial embossments 108 are 1¼ inches in width 113. The radialembossments 108 are preferably raised by {fraction (5/16)} of an inch inheight 117 from the first surface 104 of the surface plate 100 at thelocation 109 of the radial embossment 108 that intersects 109 with thecentral embossment 116. The radial embossments 108 are preferably raisedby a tapered amount away from the first surface 104 of the surface plate100 such that a radial embossment 108 is raised by ½ inch in height 117at the location 111 of the intersection between the radial embossment108 and the perimeter embossment 112. The preferred embodiment for asquare surface plate as depicted in FIG. 1 comprises four radialembossments 108 that emanate from the central embossment 116 atapproximately ninety degrees from one another. Each of the radialembossments 108 in this preferred embodiment, as depicted in FIG. 1,radiate from the central embossment 116 towards a corner 101 of thesurface plate 100.

[0034] Various orientations and numbers of radial embossments arecontemplated within the scope of the present invention. As shown inFIGS. 1 and 3, surface plates may have 4, 6, or 8 radial embossmentsemanating at regular spacing from the central embossment to theperimeter embossment. FIG. 3A depicts a circular surface plateembodiment of the present invention 204 with a circular perimeterembossment 208, six radial embossments 212, a central embossment 216,and a central opening 220. FIG. 3B depicts a rectangular surface plateembodiment of the present invention 226 with a rectangular perimeterembossment 228, eight radial embossments 232, a central embossment 236,and a central opening 224. FIG. 3C depicts a square surface plateembodiment of the present invention 242 with a rectangular perimeterembossment 240, six radial embossments 232, a central embossment 248,and a central opening 252. FIG. 3D depicts a circular surface plateembodiment of the present invention 258 with a circular perimeterembossment 260, eight radial embossments 256, a central embossment 264,and a central opening 268. These examples are meant to be illustrativeof the present invention and not limiting. Those of skill in the artwill recognize additional variations on the spacing, shape, and numberof radial, central and perimeter embossments.

[0035] In one presently-preferred embodiment, shown in FIG. 5, thesurface plate 500 has a first surface 504 that is generally planar butfor a plurality of embossments 508, 512, 516. A perimeter embossment 508extends around the surface plate proximal to the outer perimeter of thesurface plate 500 approximately {fraction (1/2 )} inch from theperimeter. This perimeter embossment 508 is raised ½ inch from the firstsurface 504. A central embossment 516 is located centrally on the plate500 and on the first surface 504 and is generally symmetric about anopening 520 defined by the plate 500 on the central embossment 516. Thecentral opening 520 is designed to accept a bolt and is at least thediameter of the mine roof bolts being used in the application for whichthe surface plate 500 is being used. The central embossment 516 has adiameter approximately ten times the diameter of the central opening520. The central embossment 516 protrudes {fraction (5/16)} of an inchfrom the first surface 504 in the same direction that the perimeterembossment 508 extends from the first surface 504. A 6 inch×6 inchbearing plate will thus contact only the central embossment 516 whenused with the surface plate 500 in conjunction with a roof bolt. A 8inch×8 inch bearing plate will also, generally, only contact the centralembossment 516 but will overhang from the diameter of the centralembossment 516 and thus may contact a radial embossment 512 near wherethe radial embossments 512 intersect the central embossment 516. In thepreferred embodiment depicted in FIG. 5, the central embossment 516 isat minimum 1¼ inches from the perimeter embossment 508. The perimeterembossment 508 is approximately 1 inch in width at its widest point andis approximately ½ of an inch from the perimeter edge of the surfaceplate 500 and the first surface 504.

[0036] In the preferred embodiment depicted in FIG. 5, four radialembossments 512 extend from the central embossment 516 to the perimeterembossment 508. In this regard, the radial embossments 512, theperimeter embossment 508 and the central embossment 516 are connected toform one nearly continuous embossment on the first surface 504. A secondsurface 524 opposite the first surface 504 on the surface plate 500comprises a generally planar surface with recesses corresponding to theperimeter embossment 508, the central embossment 516 and the radialembossments 512. The second surface 524 thus has the inverse topographyas the first surface 504.

[0037] The four radial embossments 512 protrude from the first surfaceapproximately {fraction (5/16)} of an inch from where they intersectwith the central embossment and generally decrease in height as theyextend from the central embossment 516 to the perimeter embossment 508such that the radial embossments are ½ of an inch in height where theyintersect with the perimeter embossment 508. The radial embossments areapproximately 1¼ inch in width where they intersect the first surface504. A cross-section of the perimeter embossment 508 is generallytriangular with a generally small flat surface 509 at the apex of thetriangle at the greatest height of the embossment 508 above the firstsurface 504, except in the corner intersections of the perimeterembossment 508 and the radial embossments 512 where a larger flatsurface is formed 510. The radial embossments 512 also have a generallytriangular cross-section with a small flat surface 513 at their apex atthe greatest height they attain above the first surface 504. The centralembossment 516 is generally rectangular in cross-section and forms agenerally planar surface upon which a bearing plate may bear.

[0038] The surface plate 500 depicted in FIG. 5 is generally 15½inches×15½ inches in size. One skilled in the art will recognize,however, that the size of the plate 500 may be varied in accord with theneeds of the application and desires of the user. Note that the corners528 of the surface plate 500 are rounded as are the corners 532 of theperimeter embossment 508.

[0039] Note that the embossments 508, 512, 516 will form four areas 536of the first surface 504 that are bounded by the central embossment 516,two radial embossments 512 and the perimeter embossment 509. Theintersections between the embossments 508, 512, 516 also are rounded.

[0040] Several comparative tests were performed usingpresently-preferred embodiments of the present invention with radialembossments and a circular surface plate with a perimeter embossment.The plates are preferably fabricated from 20 gauge (0.0359 inchthickness) sink steel. Two preferred embodiments of the presentinvention having square shapes were tested each having differentarrangements of radial embossments. Each embodiment was a 17 inch squaresteel surface plate. A third surface plate used in the tests was a 19inch diameter circular surface plate having a perimeter embossment. Onepreferred embodiment of the present invention had four radialembossments (similar to FIG. 1) and one preferred embodiment had eightradial embossments (similar to FIG. 3B). Two variations of the squareradial embossment surface plate were used. One preferred embodimentcomprises radial embossments that emanate from the central embossment tothe corner of the perimeter embossment diagonally across the face of thesurface plate. A second preferred embodiment comprises radialembossments that emanate from the central embossment to the center of aface of the perimeter embossment parallel to the sides of the surfaceplate. All surface plates have a 1 inch diameter center hole or opening.

[0041] A laboratory test was performed to evaluate performance of thesurface plates. FIG. 4 shows the basic test set up 300. The testinvolved setting a surface plate 316 on two supports 304, 308 (two-pointtest) 14 inches apart then applying a load 312 to the center of thesurface plate 316. The center load 312 was applied through a 6 by 6 inchbearing plate 320. Both loads 312 and deformations of surface plateswere measured during these tests. The square surface plates 316 weretested with the supports 304, 308 parallel to the edges of the surfaceplate 316 as well as at a 45 degree angle to the surface plate 316 toevaluate the diagonal surface plate 316 properties.

[0042] A load-deformation relationship was measured for each surfaceplate and several variable characterizing the strength of the surfaceplate were measured. Table 1 gives the stiffness and yield and peakstrengths for the surface plate tests. The stiffness was calculated asthe secant from the “no load” condition to the yield strength. Theenergy is defined as the area under the load-deformation curve up toyield. Strength, Stiffness, Energy, lbs Deformation, Yield, Yield, Area,Plate Type Peak Yield Yield, in lbs/in in-lbs in² Square (17 in) 886 8000.6 1400 220 289 4 radial embossment, parallel Square (17 in) 1375 12901.7 760 1100 289 4 radial embossment, diagonal Square (17 in) 550 4500.4 1133 94 289 8 radial embossment, parallel Square (17 in) 825 725 1.4520 500 289 8 radial embossment, diagonal Circular 520 310 0.2 1531 34284 (19 in)

[0043] Much of the deformation, surface plate yield, and failure resultfrom bending of the surface plates. Some deformation may result frompunching of the bearing plate into the center of the surface plates.

[0044] The four radial embossment square surface plate has the highestyield and peak load while the circular surface plate has the loweststrength. The four radial embossment square surface plate hasparticularly higher strength as compared to the other tested surfaceplates. The surface area of the circular surface plate is 283 squareinches, while the surface area of the square surface plates was 289square inches.

[0045] Among the preferred embodiments of the present invention, thefour radial embossment square surface plate is significantly strongerthan the eight radial embossment square surface plate. The four extraradial embossments in the eight radial embossment square surface plateparallel to the surface plate edges may act to weaken the surface plateessentially by providing a weak point or crease where the surface platemay bend. This result highlights the fundamental importance of theinternal structure of the surface plates. The strength of thepresently-preferred surface plates of the present invention is muchhigher when tested across the diagonals. This is believed to be theresult of more material and structure in the corners that adds strengthto the surface plate across the direction of bending.

[0046] The circular surface plate and the 17-inch four radial embossmentsquare surface plate have approximately the same stiffness with thecircular surface plate having slightly higher stiffness. Much of thisstiffness appears to come from the external or edge structure, namelythe perimeter embossment, of the surface plates. The stiffness of aprior art square flat plate without any internal embossments wasmeasured at 35 pounds/inch. The stiffness of the square and circularsurface plates was thus significantly higher than the stiffness of aprior art plate.

[0047] Although the invention has been described in terms of particularembodiments in an application, one of ordinary skill in the art, inlight of the teachings herein, can generate additional embodiments andmodifications without departing from the spirit of, or exceeding thescope of, the claimed invention. Accordingly, it is understood that thedrawings and the descriptions herein are proffered only to facilitatecomprehension of the invention and should not be construed to limit thescope thereof.

What is claimed is:
 1. A surface plate for use in supporting a mineroof, said surface plate comprising: a first surface adapted to faceaway from said mine roof, wherein said first surface defines a centralopening capable of receiving a mine roof bolt, and said first surfacefurther comprising: a first embossment centrally located on said firstsurface, wherein said first embossment comprises a circular raised planesurrounding said central opening, further wherein said raised circularplane is generally parallel to said first surface; a second embossmentlocated on said first surface, wherein said second embossment comprisesa continuous raised surface that is proximal to the outer perimeter ofsaid first surface; a plurality of radial embossments, wherein each ofsaid plurality of radial embossments extend from said first embossmentto said second embossment and intersect with said first embossment andsaid second embossment; and a second surface adapted to face said mineroof, wherein said second surface is generally planar, further whereinsaid second surface comprises a complementary face to said first surfacecomprising a plurality of recesses corresponding to said first andsecond embossments and said plurality of radial embossments.
 2. Thesurface plate of claim 1, wherein said surface plate is rectangular,circular, or elliptical.
 3. The surface plate of claim 2, wherein saidplurality of radial embossments is selected from the group consisting offour, six, and eight.
 4. The surface plate of claim 3, wherein saidplurality of radial embossments are spaced at regular intervals aroundsaid first embossment.
 5. The surface plate of claim 1, wherein saidfirst embossment is raised {fraction (5/16)} of an inch from said firstsurface.
 6. The surface plate of claim 1, wherein said first embossmenthas a diameter that is ten times larger than the diameter of saidcentral opening.
 7. The surface plate of claim 1, wherein said secondembossment continuously parallels the outer perimeter of said firstsurface.
 8. The surface plate of claim 1, wherein said second embossmentis ½ inch from an outer edge of said surface plate.
 9. The surface plateof claim 1, wherein said second embossment is one inch in width.
 10. Thesurface plate of claim 1, wherein said second embossment is raised ½ ofan inch from said first surface.
 11. The surface plate of claim 1,wherein said plurality of radial embossments are raised from said firstsurface by ½ of an inch at the locations where said plurality of radialembossments intersect said second embossment.
 12. The surface plate ofclaim 12, wherein said plurality of radial embossments are raised fromsaid first surface by {fraction (5/16)} of an inch at the locationswhere said plurality of radial embossments intersect said firstembossment.
 13. The surface plate of claim 12, wherein said plurality ofradial embossments are raised a tapered amount, further wherein saidtapered amount is {fraction (5/16)} of an inch at the locations wheresaid plurality of radial embossments intersect said first embossment and½ of an inch at the locations where said plurality of radial embossmentsintersect said second embossment.
 14. The surface plate of claim 13,wherein said tapered amount varies smoothly between {fraction (5/16)} ofan inch and ½ of an inch.
 15. A surface plate for use in supporting amine roof, said surface plate comprising: a first surface adapted toface away from said mine roof, wherein said first surface defines acentral opening capable of receiving a mine roof bolt, further whereinsaid first surface is generally square, and wherein said first surfacefurther comprises: a first embossment centrally located on said firstsurface, wherein said first embossment comprises a circular raised planesurrounding said central opening, further wherein said raised circularplane is generally parallel to said first surface; a second embossmentlocated on said first surface, wherein said second embossment comprisesa continuous raised surface that generally parallels the outer perimeterof said first surface; four radial embossments, wherein each radialembossments extends from said first embossment to said second embossmentand intersects with said first embossment and said second embossment,further wherein said four radial embossments are spaced regularly aroundsaid first embossment, further wherein each radial embossment extendsfrom said first embossment to said second embossment and intersects saidsecond embossment at a corner of said second embossment wherein saidcorner of said second embossment corresponds in location to a corner onsaid outer perimeter of said first surface; and a second surface adaptedto face said mine roof, wherein said second surface is generally planar,further wherein said second surface comprises a complementary face tosaid first surface comprising a plurality of recesses corresponding tosaid first and second embossments and said four radial embossments.